Biodegradable drains for medical applications

ABSTRACT

The invention relates, generally, to medical appliances. More particularly, it relates to tubular shaped devices used as drains for draining fluids (liquids and/or gases) from antrums or other parts of the human or animal body. According to the present invention a drain is provided, which is suitable for draining a human or animal antrum, which drain comprises a synthetic biodegradable material, preferably a biodegradable polymer.

The invention relates, generally, to medical appliances. Moreparticularly, it relates to tubular shaped devices used as drains fordraining fluids (liquids, viscous substances and/or gases) from antrumsor other parts of the human or animal body.

In both human and veterinary medicine, it is often desirable to getaccess to an antrum in order to discharge pus or other material whichmay form as a result of inflammatory conditions. This is for instancethe case with (chronic) sinusitis or inflammatory conditions in themiddle ear.

Chronic sinusitis symptoms can be difficult to treat, in part becausetreatment may require the coordinated efforts of several specialists totreat all of the aspects of the disease. Chronic sinusitis can be brokendown into bacterial chronic sinusitis and non-infectious chronicsinusitis. Both have different medical treatment options. Many peoplewith non-infectious chronic sinusitis respond to topically or orallyadministered steroids or nasal wash treatments.

Depending on the severity of the sinusitis, there are several treatmentsto consider such as antibiotics and sinus surgery. Sinus surgery isgenerally a last line of defense for doctors to relieve a sinusitiscondition. In this type of surgery the natural opening to the sinuses isenlarged. The procedure includes removal of areas of obstruction, withthe aim of reinstating the normal flow of mucus.

Unfortunately the newly created opening or connection between the sinusand the nasal cavity has the tendency to re-narrow (restenose)necessitating a re-intervention. Therefore, sinus-nasal stents, drainsor cannula's have been developed to further improve the result of thedrainage procedure. U.S. Pat. No. 4,737,141 discloses a method to drainthe maxillary sinus with a temporary biodurable plastic drain, byplacing the drain in an artificially created opening in the maxillarycavity, which method is an improvement of the classical treatment withmultiple lavages of the antrum.

However, a drawback of the currently available drains is that they needto be removed in due time. Removal of these drains may damage the newdrainage tract causing it to re-occlude. Moreover, the procedure istime-consuming and unpleasant for the patient.

In a majority of cases the drains according to the state of the art areleft in place only for a short period of time before they are removed.However, in some cases it is desirable to leave the drain in place for alonger period of time e.g. because the antrum, surrounding tissue oranatomical structure needs more time to heal. Known nasal drainage tubesmay be left in place for as long as 6 months or more to drain an antrum.

Leaving these known drains in place for a long period of time may leadto complications. The materials used for known drains (usually plastic)may induce irritation but may also induce an inflammatory response.Inflammatory responses may lead to the formation of scar tissue, whichin it self, may require treatment, especially when this occurs in thenatural drainage pathway of an antrum. Furthermore, removal of thesedevices may traumatize the surrounding tissue due to mechanical forcesand since newly formed tissue may have attached firmly to the device, itis also possible that the tissue grows attached to the device andpulling it free may consequently damage the tissue.

Apart from the application in draining fluids or gases from antrums,drains are also applied to drain fluids or viscous substances fromorgans or tissue. In surgically operated areas a drain is left behindfor several days to drain the tissue fluid. Also drains can be applieddirectly to organs if the effluent of that organ can not by drained viathe natural route. Sometimes drains become blocked or occluded so thatthey have to be removed or replaced. Especially when the drain has to beapplied for a longer period of time it may become fixed in the body,making removal very difficult or even impossible and not withoutdiscomfort and risk for the patient.

Disorders in the colon and esophagus such as inflammation, carcinomas,diverticulitis, perforation, etc., frequently require resection of asegment of the intestine. After the resection, the proximal and distalsections of the intestine are reconnected, which operation is known asanastomosis. Anastomotic dehiscence or leakage is one of the majorproblems associated with coloanal anastomoses in the middle or lowerrectum, or anastomoses in the esophagus. A temporary colostomy may beplaced to reduce the risk of leakage by giving time to intestinalhealing, but the construction and closure thereof is associated with ahigh morbidity and mortality. Instead of placing a temporary colostomy,a protective drain can be placed as an inner lining of the intestines toprotect the wound and the interior of the body cavity from contaminationwith the intestinal contents and to promote healing of the wound. Thecontents of the colon or esophagus (feces or food, respectively) maythen pass in a natural way.

U.S. Pat. No. 4,719,916 and U.S. Pat. No. 4,905,693 disclose anintra-intestinal bypass graft of a thin walled latex or silastic tube.It is placed as a lining to protect the intestinal mucosa from contactwith food and/or feces. The graft is stapled or sutured to the mucosaand passes from the body naturally after a certain period of time. Adisadvantage is that the disappearance of the graft has to be proven byX-ray. A bio-fragmentable ring made of polyglycolic-acid has been usedto make a sutureless anastomosis. The use of this ring is described invarious publications among which German patent DE-A-40 42 248 and iscommercially available under the name ‘Valtrac™’. However, fastdegradation of glycolic-acid may cause severe tissue reactions.Furthermore, the ring is brittle and stiff which may cause restenosis ofthe lumen so that the natural peristaltic motions are suspended.

U.S. Pat. No. 5,129,889 describes an epidural catheter made of asynthetic biodegradable polymer, used for repeated or continualinjections of anesthetic agents. The catheter has no drainage function.It mentions homopolymers of cyclic monomers, such as dioxanone andcaprolactone; polylactide; polyglycolide; copolymers of glycolide andlactide; copolymers of a cyclic monomer, such as ε-caprolactone andglycolide or lactide as suitable materials for the catheter. There is,however, little information on suitable compositions of such polymers inU.S. Pat. No. 5,129,889.

U.S. Pat. No. 5,201,724 describes a catheter for bodily fluids, inparticular for urine, consisting of a tube of a non-biodegradableconventional flexible material such as NR, PVC, PU, PTFE and siliconerubber. To this supporting tube of conventional material there isapplied a layer of a biodegradable material, which hydrolyses in theurinary fluids to give acidic degradation products. The biodegradablematerials mentioned in U.S. Pat. No. 5,201,724 are polylactides,polyglycolides and polybutyrates. This known catheter does not solve theabove-mentioned problems associated with subsequent removal of thecatheter.

U.S. Pat. No. 4,650,488 discloses prosthetic devices formed ofbiodegradable material useful as an ear ventilation tube and fordraining otitis media from the middle ear. These known prostheticdevices are to retain at least some structural integrity.

The device is based on, for example, poly(DL-Lactide),poly(DL-lactide-co-glycolide) or poly(caprolactone). The polymers have amonomer composition that results in a stiff material at body conditions.

U.S. Pat. No. 2,593,980 (1952) discloses a surgical drainage tube whichis absorbable by the human system and provided with a plurality ofperforations on one end. It is not specifically used for drainingantrums, but it is mentioned that the drain can be inserted e.g. throughthe mouth into the stomach. The biodegradable material is preferablycatgut, a naturally occurring material (collagen).

Biodegradable materials originating from a natural source, for exampleType I collagen, hyaluronic acid derivatives, polysaccharides andchitosan, have been used in various medical applications. Thesebiomaterials have some disadvantages e.g. the properties of naturalpolymers are difficult to control; they may have batch to batchvariations, and they are generally more expensive than syntheticmaterials. Also, biodegradable material of natural sources, especiallyof animal origin, is not preferred to be used, because of the biologicalhazards associated with its use. Synthetic materials usually do notsuffer from these disadvantages.

Accordingly there is a need for a novel, temporary drain, which drain isflexible and remains functional in the body or antrum orifice for theduration of the prescribed, clinical appropriate period of time toaccomplish the predetermined therapeutic purpose.

It was found that this can be obtained by providing drains made from abiodegradable synthetic material having a phase transition temperatureof at most mammalian body temperatures (which is generally 37° C. forhumans). Thus, the present invention relates to a drain suitable fordraining a human or animal antrum, organ or tissue characterized in thatit comprises a biodegradable synthetic material. The biodegradablematerial is preferably a biodegradable synthetic polymer.

A drain is defined herein as a tube, optionally having perforations (inparticular pores), which is placed into an antrum, organ or tissue by anatural body orifice or by an artificially created orifice in the wallof an antrum or in an organ or tissue. An “antrum” is defined herein asa natural occurring body cavity which may also be a lumen. The functionof the drain is to carry fluids (such as liquids, viscous substancesand/or gases). A drain differs from a stent in that stents are used tomechanically support lumen walls (such as in blood vessels or ureteralpassages) in case of strictures or obstructions. Stents are designed ina such a way that they can withstand radial stresses. The stent must benon-elastic at body conditions and must therefore be composed of amaterial with a specific strength and stiffness. These mechanicalproperties are different from those of drains, which are preferablyflexible and elastic. Also, since drains generally do not have tosupport lumen walls, the resilience may be lower than that of stents.Stents are usually placed in lumens to assist the normal liquidtransport in the body (such as blood circulation or urine transport fromkidney to bladder). Drains assist the natural channels in the body thatcarry body fluids, in general from the antrum, organ or tissue to theenvironment outside the body or to another location in the body. Drainsmay also perform itself as an artificial channel in the body. Alsoregarding its degradation behavior, the drains of the present inventiondiffer from biodegradable stents. The degradation of biodegradablestents usually starts and continues from the inner core towards theouter layer. In particular when stents are applied in blood vessels, itis very important that no fragments of partially degraded material arereleased on the inside of the tube, since this could lead to migrationof these fragments through the body, which would be hazardous. In thedrains according to the present invention, however, the degradation maycommence and propagate on the outside towards the inside or in the bulk,optionally under influence of the fluids that are drained. Iffragmentation occurs, this generally does not present any problems,since these fragments are transported to locations (such as theenvironment or the oral cavity) were they can do no harm. Fragmentationmay be even an advantage, since the fragments of the biomaterial canleave the body after the drain has fulfilled its function, withoutnecessarily being re-sorbed by the body.

The drain of the present invention may be essentially cylindrical (viz.having a constant cross-section) or its cross-section may vary in orderto suit specific applications, e.g. by providing it with a funnel shapedend, as will be described hereinbelow in more detail. It is alsopossible according to the present invention to provide a drain that iscreated in situ in the human or animal body by providing a device withone open end, which is subsequently processed in such a way that itbecomes a drain, i.e., a tube with two open ends.

Synthetic biodegradable materials such as polymers have been used formany medical applications that require only a temporary presence of adevice in the body. Devices of biodegradable materials are used mainlyin tissue repair and drug delivery. These materials can be used asfilms, sheets, tubes, plugs, pins, rods, fibers, ligaments, scaffolds,microspheres, membranes, and so forth. These products, which can besolid or porous, can have all kind of shapes. Devices of biodegradablematerial have been used as an implant or in wound closure, as wounddressings, artificial skin or in drug delivery and can be applied in themucous membrane tissue by insertion via a body orifice e.g. for tissuerecovery after a surgical procedure or an injury.

The majority of biocompatible, biodegradable synthetic materials thatare being used in medical devices is based on synthetic polyesters madeof (mixtures of) cyclic lactones such as glycolide, lactide,ε-caprolactone, para-dioxanone, trimethylenecarbonate and of polyestersmade by a condensation reaction of diols and diacids or hydroxyalkanoicacids. These polyesters can be used as such or in combinations withpolyethers, polyurethanes, polyamides or with organic or inorganiccompounds. A wide range of medical devices has been developed and/ormanufactured so far of these types of biomaterials.

WO-A-03/66705 discloses the use of a copolymer of DL-Lactide andε-caprolactone with a specific composition in the manufacture of abiodegradable nerve guide, which is a flexible, solid tube. A specificmonomer composition is required to supply the product with the bestperformance properties such as mechanical strength, softeningtemperature and compression modulus.

U.S. Pat. No. B2-6,423,092 discloses a biodegradable stent forimplantation in a body lumen made of two layers of a differentbiomaterial composition, resulting in a different degradation rate ifthe inner and outer layer. This type of stent is being developed forreplacing permanent stents, e.g. for treating stenosis of the lumen inurological applications.

In U.S. Pat. No. 5,085,629 a bioresorbable ureteral stent made of aterpolymer of lactide, glycolide and caprolactone is disclosed.

The materials properties (mechanical, physical and degradation) of thedrains of the present invention are different from those of previouslydescribed stents or drainage tubes and are specific for application of abiodegradable drain. The properties of the drain according to thepresent invention will be discussed in more detail in the description ofthe preferred embodiment.

A drain of a synthetic biodegradable material will have the advantagethat it degrades over time where after it is being resorbed and/orexcreted by the body. This has the advantage that no additionalintervention is required to remove the device, but also that theincidence of adverse events and complications, associated with theremoval procedure is reduced. Since the biodegradable drains are similarin design to the conventional biodurable devices, rinsing of the antrum,which is desired in some clinical cases, remains possible.

An example of such a biodegradable drain tube could be the drainage ofbile from the liver. This is required in patients where the natural bilesecretion pathway has become blocked, e.g. due to tumor growth or livernecrosis.

The drain can be used until it becomes blocked. A biodegradable draincan be used longer than the biodurable version since the biodurableversion has to be removed before it becomes occluded and attached in thebody. In contrast to conventional biodurable drains, which have to beremoved, which action brings patient risk and discomfort, thebiodegradable drain according to the present invention is left in placewhere it degrades and is being absorbed over time. If desired, aftersome time a new biodegradable drain according to the invention may beplaced to take over the function of the previous one.

The use of biodegradable and bio-resorbable materials for manufacturingmedical devices having a temporary function is well known and commonpractice. In general, the use of a biodegradable device may prevent thepotential complications associated with biodurable devices when used forboth short and longer periods of time.

The present invention provides a device for draining an antrum which iscomposed of a synthetic biodegradable material and which is easilypassed from the body or antrum orifice after a specific therapeuticperiod of time.

The biodegradable drain of the present invention can be employed fortreating frontal and maxillary sinusitis. Preferably the drain has adistal end that is shaped in such a way that it is easily retained inthe sinus cavity (anchor). The drain can be inserted through the naturalorifice or through a surgically created opening. The drain can beintroduced e.g. by the use of a forceps, a guidewire, a trocar orunsupported. The biodegradable drain of the present invention mayfurther be used for draining tear fluid from a nasolacrimal duct.

Furthermore, a biodegradable drain can be applied in the digestivetrack. Such a drain can be inserted through a natural body orifice e.g.by means of a surgical stapler and can subsequently be fixated to thetissue by stapling.

The biodegradable drain of the present invention may further be used fordraining tear fluid from a nasolacrimal duct. The present inventionprovides drains made of biodegradable synthetic polymeric materials,which degrade with such a rate giving the surrounding tissue time toheal, maintaining an opening of the antrum or lumen and without damagingthe surrounding tissue when it degrades. The degradation products ofthis biocompatible, biodegradable drainage device are cleared either viathe digestive channel, the body or antrum orifice or absorbed by thebody and metabolized and/or secreted.

FIG. 1 shows a straight biodegradable drain of the present invention.

FIG. 2 shows an example of a biodegradable frontal sinus drain of thepresent invention.

FIG. 3 shows an example of a biodegradable ear vent of the presentinvention.

The drain according to the present invention, comprises cylindricaltubes (drains) of appropriate sizing (outer diameter: from 0.5-50 mm,total length of 3-300 mm, wall thickness from 0.05-5.0 mm) for beingused in draining various antrums or organs. As shown in FIG. 1 the draincan be a hollow tube of substantial length and diameter for beingapplied as a nasolacrimal duct to temporarily drain the tear fluid whereafter the tube degrades and the original nasolacrimal duct takes overits function. Straight tubing is, in general, suitable for drainingantrums or organs where fixation in the anatomical location by a specialtube design is less critical as in the case of the nasolacrimal duct. Inthe application of a drain in the intestinal tract, it is preferred thatthe drain is sutured or stapled to the tissue.

FIG. 2 shows a drain which may be used as a frontal sinus drain inaccordance with the present invention, supplied with a funnel (6) at oneend of the tube. The drain is characterized by a wall thickness (1), aninner diameter (2), an outer tube diameter (7), a tube length (3), afunnel length (4) and funnel diameter (5). The funnel ensures fixationof the tube in the antrum. This funnel shape is highly preferred overconventional shapes employed for this purpose, such as the “split-end”type of anchoring described in U.S. Pat. No. 4,737,141. It was foundthat these conventional anchoring means provide for dead spaces orvolumes in which stagnant fluid may collect, which in turn form a sourceof microbiological activity, which may lead to further complications.According to the present invention it is possible to provide anchoringmeans, such as the funnel shape depicted in FIG. 2, with a smooth andcontinuous surface, by which these problems can be avoided.

Typically, the tube of FIG. 2 may be used for draining the frontaland/or maxillary sinus. The device can be made out of one piece. Thesize of the funnel may vary from 3-30 mm in inner diameter and 2-20 mmin length. The dimensions of the cylindrical part are related to eachother as in the case of the tube of FIG. 1.

Another embodiment of a drain of the present invention is seen in FIG.3. A cylindrical tube of a single piece, with two flanges, one on eachside. A possible application, but not restricted to this, is thedrainage of the middle ear. The tube is intended to vent the middle earand is placed in the tympanic membrane. The tube is placed in anartificially made puncture in the membrane.

The dimensions of the drains and relative dimensions of parts of thedrain of FIG. 1-3 will depend on a number of factors, including theanatomy of the patient and the type of surgical procedure.

According to the invention the drain is made of a syntheticbiodegradable material. A biodegradable material may be completelyresorbed by the body or may degrade by fragmentation of the material.The fragments are cleared either via the digestive channel or via anantrum orifice.

In a more preferred embodiment, the biodegradable material is asynthetic polymer. The polymeric material can be a thermoplastic linearpolymer or a thermoset polymer obtainable by cross-linking of(pre)polymers. Examples of synthetic biodegradable polymers that can beapplied for manufacturing the drains of the present invention are basedon polyesters, polyhydroxyacids, polylactones, polyetheresters,polycarbonates, polydioxanones, polyanhydrides, polyurethanes,polyester(ether)urethanes, polyurethane urea, polyamides,polyesteramides, poly-orthoesters, polyaminoacids, polyphosphonates andpolyphosphazenes. The polymeric material may also be composed ofmixtures of above components either as different building blocks of thecopolymer or cross-linked polymer or as a blend of two or more(co)polymers. Composites of these polymers with organic and inorganiccompounds (e.g. radiopaque fillers) are also possible. In addition, thepolymer may be loaded with pharmaceutical components such asantibiotics, anti-inflammatory agents, anaesthetics, proteins and manymore. The polymer can be loaded with pharmaceutical components by mixingthe components (e.g. pure or dissolved in a solvent such as water) withthe polymer solution, after which the solvent is evaporated and/orfreeze dried. Mixing is performed preferably with a turrax homogenizer.

Evidently, the possibilities are not limited to the above mentionedpolymers but also other materials may be used, as long as they aresynthetic, biodegradable and biocompatible and possess the desiredmechanical, physicochemical and degradation properties. Polymers are thepreferred materials, since they enable the design of drains having thedesired properties (such as degradation behavior and mechanicalproperties) by selecting the proper synthesis conditions for thepolymer.

The preferred biodegradable polymers used for drains according to thepresent invention, are those based on polyesters, polycarbonates,polyanhydrides, polyurethanes and/or polyamides, viz. the preferredbiodegradable polymers comprise ester (—C(O)—O—), carbonate(—O—C(O)—O—), anhydride (—C(O)—O—C(O)—), urethane (—NH—C(O)—O—) and/oramide (—NH—C(O)—) groups. These polymers usually degrade throughhydrolytic cleavage of the ester, carbonate or anhydride linkages.Enzymes or other bio-chemically active compounds may assist thishydrolytic cleavage and that of the urethane and amide bonds. The rateof degradation of the polymers can be regulated by choosing the contentand combination of monomers.

Urethane and amide groups are usually present in combination with one ormore of the polyester, polycarbonate or polyanhydride groups. Thepolyesters, polycarbonates or polyanhydrides without the presence ofurethane or amide groups can either be homopolymers or copolymers. Thecopolymers can be random or can be block—or segmented copolymers.

In case the biodegradable polymer has a phase separated morphology, afirst block is based on the polyesters, polycarbonates and/orpolyanhydrides mentioned above. This first block is also referred to asthe “soft” block and is amorphous with a glass transition temperaturebelow mammalian body temperature at physiological conditions. The other(second) block or segment forms a crystalline hard block at theseconditions such as urethane, amide, or it contains a polyester- orpolyanhydride which is either crystalline or amorphous and having aphase transition larger than 37° C. (melting temperature or Tg).

The biodegradable polymer can also be combined with hydrophilicpolymers, such as polyethers, polyvinylalcohol, polyvinylpyrrolidone orpoly(hydroxymethylmethacrylate) (poly-(HEMA)). This means that theabove-mentioned (co-)polymer chains are chemically combined with thesehydrophilic polymers, e.g. by choosing synthesis conditions that allowincorporation of the hydrophilic polymers in the backbone or in theside-chain of the resulting copolymer. The hydrophilic polymer ispreferably a polyether, more preferably a polyethyleneglycol. Othersuitable polyethers are polytetramethyleneoxide (PTMO) and copolymers ofe.g. polyethyleneglycol and polypropyleneglycol. The preferred molecularweight and amount of the polyethers is dependent on the hydrophilicproperties that are demanded by the product. The polyethers can be mixedor can be a pre-polymer in combination with the biodegradable(pre)polymer.

The relative amounts of components must be chosen in such a way that aproduct with the desired physicochemical, thermal, mechanical,hydrophilic and degradation properties is obtained.

A drain for the above mentioned applications must be flexible, pliableand elastic. These properties can be obtained by using an appropriateprocessing method. For example, by winding of polymeric fibers into acoiled spring structure or by knitting or weaving of fibers, an openstructured tube with above mentioned properties can be obtained,optionally followed by a dip-coating run to close the openings.Preferably, the drain is obtained by dip-coating or spray coating of apolymer solution on a mandrel or extrusion of a polymer. A solid tube isthen obtained, after which perforations or carvings can be made.

By using a material with at least one softening point (Tg) equal to orbelow mammalian body temperatures (typically 37° C. for humans, but thismay be higher, for instance in case of fever, when it may be as high as41° C.) according to the present invention, drains are obtained, whichhave suitable elastomeric properties when placed in the body. The termsoftening point (Tg) as used herein, is defined herein as the firstinflection point in a DSC (Differential Scanning Calorimetry) curvestarting from low temperature upwards. It is to be understood that Tgrefers to the Tg of a material when applied in vivo; viz. when atequilibrium with an atmosphere that is saturated with water vapor and atbody temperature. Thus the materials of the present invention and thefact that at body conditions they have at least one softening point(glass transition temperature) of at most mammalian body temperature isreflected by the fact that these materials are flexible and preferablyalso elastic when applied at these body conditions. Alternatively, (invitro) DSC measurement may be performed on the material after allowingthe material to equilibrate with a water-saturated atmosphere atmammalian body temperature (typically this takes several minutes to onehour or more, such as 5 minutes or 30 minutes to 2 hour, or even to oneday). When in dry state, the materials used in the present invention mayhave Tg values that are somewhat higher than mammalian body temperature,that is to say, when the dry materials are subjected to DSC, the firstinflection point may arise at higher temperatures, for instance at 42 or50° C., or more. Upon application in vivo, however, the dry material'sTg will drop as a result of the absorption of water and this final Tgshould be about body temperature or lower according to the presentinvention.

The physical cross-links that are required for the elastomericproperties can be formed by chain entanglements which are present in anamorphous, high molecular weight copolymer or, in case of a phaseseparated copolymer, by crystalline or high Tg segments with a meltingor glass transition temperature higher than 37° C. Drains based onmaterials with chemical cross-links can be made when the pre-polymer andcross-linking agent are mixed and reacted in a predetermined shape e.g.by reacting in a mould or extruding the mixture of reacting components.

It is preferred to make the drain in one piece from a thermoplasticelastomeric polymer by a dip-coating or spray coating process. In thedip-coating process, a mandrel, having the shape of the drain to beobtained and which thus functions as the template for the drain, issubmerged in a solution of the polymer (usually an organic solvent).After the mandrel is removed from the solution, a layer of solutionremains adhered to its outer surface. Subsequently the solvent isevaporated. Optionally the procedure may be repeated to obtain drainshaving a higher wall thickness. In the spray-coating process, a polymersolution is sprayed on the rotating mandrel after which the solvent isevaporated. Several layers can be sprayed on the mandrel to obtain thedesired thickness of the drain. Drains with various dimensions can bemade in this way, depending on the dimensions of the mandrel. Thethickness of the drain can be regulated by the number of dip- or spraycycles. Also, the drain can be made by extrusion. In this case, thepolymer should be thermally stable, should not contain chemicalcross-links and should not have a too high melting temperature or meltviscosity.

A biodegradable drain made of a synthetic polymer is preferably aflexible solid tube (with or without perforations) with an elasticmodulus varying from 1-120 MPa. More preferably, and in particular forfrontal sinus drains, the elastic modulus is 2-10 MPa. Drains havepreferably a tensile strength of more than 2 MPa at an elongation atbreak of 500-1300%, more preferably the drains have a tensile strengthof more than 5 MPa.

A polymeric material that fulfils all of the criteria will be acopolymer of lactide and ε-caprolactone. The lactide can be L, D orD,L-Lactide. The lactide content is preferably between 51-75%, becausethere is little or no swelling of the material with this composition.Too much swelling may lead to obstruction of the lumen so that drainageis prohibited. Most preferably, the lactide content is 62-69% and havinga L/D ratio of 85/15 or 15/85. In case a racemic lactide is used, themolecular weight of the copolymer must be high enough to obtain a tubehaving the desired mechanical properties. The physical cross-links thatgive the material its elastic properties are caused by chainentanglements that can only be present if the molecular weight is highenough. An intrinsic viscosity (which is a measure for Mw) of at least 3dl/g is very suitable in that case. In case an isomeric lactide or alactide with an L/D ratio away from unity is used, physical cross-linkscan be obtained by poly-lactide sequences. The presence of long L- orD-lactide rich sequences increases the amount of physical cross-links.Maximum physical cross-linking is obtained with an isomeric lactide(either L or D). A lower molecular weight is then acceptable. Ingeneral, the intrinsic viscosity may vary from 1-6 dl/g. The time untilthe drain starts to loose its mechanical properties will be dependent onthe starting molecular weight. A drain of a lactide-caprolactonecopolymer material will keep its performing properties for preferably atleast one week, more preferably about 2-12 weeks.

Another preferred embodiment is the use of segmented or block-copolymerscomprising polyesters, polyester-carbonates or polyanhydrides.Preferably, these polymers have at least one Tg and one meltingtemperature or two separate Tg's within a copolymer, of which at leastone transition occurs below 37° C. Also segmented or block copolymerswith only one Tg below 37° C. of mixed phases are possible. Examples ofthe amorphous soft phase forming pre-polymers are those based on cyclicand/or non-cylic monomers such as lactide, glycolide, ε-caprolactone,δ-valerolactone, trimethylenecarbonate, tetramethylenecarbonate,1,5-dioxepane-2-one, para-dioxanone and/or hydoxyalkanoic acid. Thesecond or ‘hard’ phase may be formed by pre-polymers comprisingpoly-caprolactone, poly-valerolactone, poly-lactide,poly(lactide-glycolide), poly-para-dioxanone, poly(hydroxybutyricacid),polysebacic acid or poly(dodecanedioicanhydride) and combinationsthereof. Combinations of these pre-polymers may also result in asegmented or block copolymer with a phase mixed morphology.

A suitable phase separated copolymer of this type is aDL-lactide-caprolactone copolymer with a lactide content of 20-40%. Inthis case, the ε-caprolactone content is high enough to crystallize. Theamount of crystallization depends on the ε-caprolactone content and onthe distribution of monomers. The monomers can be randomly distributedbut preferably, the polymer is a segmented or block-copolymer withcrystalline poly-caprolactone hard segments and amorphouspoly(lactide-ε-caprolactone) soft segments. The general structure ofthese phase separated copolymers is [-A-B]_(n) or ABA. n denotes thenumber of repeat units of -A-B- in case the segments A and B arealternating. [-A-B-]_(r) is the notation for a multi-block segmentedcopolymer in which the segments A and B are randomly distributed and theratio A/B is not necessarily equal to one. ABA is a triblock copolymerof segments A and B. A and B can be both the hard phase and soft phaseforming segment, but can not be the same in one copolymer. Thepre-polymer segments are preferably linked by an aliphatic diisocyanate,more preferably 1,4-butanediisocyanate. The crystallization ofpoly-caprolactone segments will yield a copolymer with a phase separatedmorphology, which will result in thermoplastic elastomeric properties.Block copolymers with structure ABA can also be chain-extended with analiphatic multi-functional molecule. A polymer with a structure[-ABA-]_(n) is then obtained.

By using this synthesis route the molecular sequence of a copolymer canbe controlled as desired for a particular application. A drain made ofthis material may keep its performing properties for several months,depending on its composition. Materials with better mechanical andthermal properties than of random copolymers of (50/50) DL lactide andε-caprolactone or lactide-caprolactone copolymers with a major lactidecontent, i.e. more than 50%, may be obtained. An elastic modulus of morethan 10 MPa can be obtained and a tensile strength of more than 5 MPa.

An amorphous drain of a segmented polyester can be obtained when atleast two different amorphous pre-polymers are chain-extended. Preferredare a combination of poly(DL-lactide) and poly(glycolide-lactide)chain-extended with 1,4-butanediisocyanate. The pre-polymer compositionand ratio can be chosen in such a way to obtain a polymer with eitherone or two values of Tg. One of the amorphous pre-polymers may beinitiated with a polyethyleneglycol (PEG). In this way, thehydrophilicity and rate of degradation can be influenced.

Another preferred embodiment is the use of biodegradable poly-urethanesfor drains. The polymer is built of alternating polyester, polyetherand/or polycarbonate containing soft segments and urethane hardsegments, giving a phase separated structure. Polymers with very goodmechanical properties can thus be obtained. Preferably, the urethanehard segments have a uniform block length which can be obtained bydifferent chain-extending methods. A polymer with the highest degree ofphase separation may be obtained by chain-extending the pre-polymer(hydroxyl terminated in case the initiator is a diol) with adiisocyanate chain-extender. Diisocyanate chain-extenders that aresuitable for obtaining polymers with uniform hard segments and withsufficient mechanical properties are e.g. diisocyanate end-capped diolcomponents, obtained by the reaction product of the diol with twoequivalents of the diisocyanate. The diisocyanate is preferably1,4-butanediisocyanate; the diol is preferably a linear aliphatic diolor a poly)ethylene glycol with general structure HO—(CH₂)n-OH with n=2-8or HO—(CH₂CH₂—O)n-H with n=1-8, respectively. Even more preferably, thediol is a reaction product of two moles of these linear aliphatic diolsor (poly)ethylene glycols with a diisocyanate, preferably1,4-butanediisocyanate (obtainable by reacting the diisocyanate with anexcess of the diol).

The phase separated segmented polyurethane can also be obtained by amethod in which the di-hydroxy terminated pre-polymer is reacted with anexcess of a diisocyanate, resulting in an isocyanate end-cappedpre-polymer. Subsequently chain-extending with a diol compound or areaction product of two equivalents of the diol with a diisocyanate willgive a phase separated polyurethane with uniform block length. As diolcompounds the above-mentioned linear aliphatic diol or (poly)ethyleneglycol compounds may be used and preferably the above-mentioned reactionproduct of these diols with a diisocyanate are used. The degree of phaseseparation may in some cases be somewhat less than obtained with thefirst given chain-extending method. This is the result oftrans-esterification reactions of labile ester groups. The polyestersoft segment is a pre-polymer build of (mixtures of) monomers such aslactide (L,D or L/D), glycolide, ε-caprolactone, δ-valerolactone,trimethylene carbonate, tetramethylenecarbonate, 1,5-dioxepane-2-one orpara-dioxanone. Optionally, polyethers are added to the polyester orpolycarbonate pre-polymers, either as an initiator or as a secondpre-polymer. The preferred polyurethane is composed of apoly(ether)ester pre-polymer soft segment and a polyurethane hardsegment with a structure -BDI-BDO-BDI-BDO-BDI-(BDI being1,4-butanediisocyanate and BDO being 1,4-butanediol). The preferredpolyether is a polyethyleneglycol. The rate of degradation of thepolyurethane will depend on the initial molecular weight (measured bythe intrinsic viscosity) and the chemical composition of thepre-polymer.

The drains of the present invention are exceptionally suitable forapplication in the digestive channel in combination with interventionssuch as coloanal or esophagus anastomoses. For this type of application,the necessary physicochemical and mechanical properties are preferablyretained from approximately 3 days to 6 weeks. The required degradationproperties may be obtained (under the applied conditions) according tothe present invention by choosing the chemical composition of thepolymer. For application in coloanal anastomoses the polymer used in thepresent invention is preferably a poly(ether)-esterurethane. Thepre-polymer for this application is preferably based on DL-lactide andε-caprolactone and having a molecular weight of preferably 1500-2300,more preferably 2000 and may be obtained by a ring openingpolymerisation initiated by 1,4-butanediol combined with the polyethercompound. The preferred monomer ratio is from 50/50 to 70/30 (mol/mol).The PEG content in the polyurethane is preferably between 1-25 wt. % forapplications in the digestive tract, more preferably from 5 to 20 wt. %.In particular, for coloanal anastomosis the PEG content is preferablybetween 2-10 wt. %. The molecular weight of PEG is preferably between600-1500 and is most preferably 1000. Phase separated polyurethanes withmolecular weights of the pre-polymer of 2000 may have an initial elasticmodulus varying from 30-120 MPa and a tensile strength of 10-45 MPa. Theelongation at break varies from 500-1200%.

The mechanical and degradation properties of the drains can easily betuned by using a physical blend of suitable polymers. For example, apolyurethane can be blended with a copolymer giving a material withintermediate properties of the components. Preferably, the soft segmentpre-polymer of the polyurethane is compatible (miscible) with thecopolymer. A DL-lactide-ε-caprolactone based polyurethane is very wellmiscible with a lactide-caprolactone copolymer, due to the miscibilityof the copolymer and pre-polymer soft segment. Drains that need to bekept in place for a much longer period of time before loosing thenecessary physicochemical and mechanical properties, such as drains forthe mid ear which may require to be put in place for a time of 6 to 9months, are preferably made of polyesters, polycarbonates,polyurethanes, poly-anhydrides, polyamides or other polymers with slowlyhydrolysable groups. The polyester or polycarbonate segments need to bebuild of slowly degrading monomers such as ε-caprolactone,δ-valerolactone, trimethylenecarbonate, tetramethylenecarbonate,para-dioxanone. Optionally, polyethers can be added.

EXAMPLES Analysis Methods and Characterization of Copolymers

The following analysis methods were used in all examples, unlessindicated otherwise.

The intrinsic viscosity ([η]), expressed in dl/g, was measured inchloroform at 25° C. using an Ubbelohde viscometer (according to ISOstandard 1628-1).

Monomer conversion and copolymer composition were determined using¹H-NMR at 300 MHz in solutions in deuterated chloroform.

Thermal properties of polymers were determined using a TAInstruments-Q1000 MDSC, 5-10 mg samples being heated at a rate of 10° C.per minute, cooled down at a rate of 20° C. per minute and heated againat a rate of 10° C. per minute. The purity and melting point of thechain-extender (BDOBDIBDO) is measured according to ASTM E-928 method.Calculations are performed with Universal Analysis program (3.4C) of TAInstruments.

Purification and/or drying of monomers and glassware was carried out inaccordance with previously published methods and was sufficient toobtain polymers with the desired properties.

Determination of Mechanical Properties of Drains:

The stress strain behavior of straight tubular drains was determinedwith an Instron 4301 tensile tester. The tubes were measured at roomtemperature at a crosshead speed of 10 mm/minute. The ultimate tensilestrength, the elongation at break and the initial modulus weredetermined from these measurements.

Example 1 Synthesis of 65:35 (85/15)L/D Lactide-ε-caprolactone

DL-Lactide and L-Lactide (ratio 70:30) (Purac, the Netherlands) wereintroduced into a reaction vessel under nitrogen atmosphere and weredried in vacuum at 45° C. for at least 8 hours. ε-Caprolactone (Acros,Belgium) is dried over CaH₂ and distilled under reduced pressure in anitrogen atmosphere.

Glass ampoules were covered inside with a teflon sheet (fluortec) anddried in an oven during one night. ε-Caprolactone was added to thelactide in the vessel in a monomer ratio 62/38 mol/mol(lactide/ε-caprolactone). The catalyst was added in an amount of 1×10⁻⁴mole of catalyst per mole of monomer. After 20 minutes of homogenisationat 120° C. the mixture was poured into the glass ampoules under nitrogenflow, after which the ampoules were closed with a stop. The ampouleswere placed at 110° C. for 312 hours (13 days). The intrinsic viscositywas 6.2 dl/g. The monomer conversion was 95%. The lactide content in thepolymer (calculated by NMR) was 65%. The glass transition temperaturewas 14.6° C.

Example 2 poly(DL-Lactide-ε-caprolactone) Prepolymer (Mn=2000)

The pre-polymer was synthesized by ring opening polymerization ofε-caprolactone and (50/50) DL lactide in a 50/50 (mol/mol) ratio using1,4-butanediol as initiator and stannous octoate as catalyst. Afterreaction at 130° C. for 5 days, ¹H-NMR showed complete monomerconversion.

Example 3 ε-Caprolactone Prepolymer (Mn=2000, 3000 and 4000)

The pre-polymer was synthesized by ring opening polymerization ofε-caprolactone using the appropriate amount of 1,4-butanediol asinitiator and stannous octoate as catalyst. After reaction at 130° C.for 5 days, ¹H-NMR showed complete monomer conversion.

Example 4 poly(DL-Lactide-ε-caprolactone) Pre-polymer (Mn=2000)Containing 13 wt. % PEG1000

The pre-polymer was synthesized by ring opening polymerization of(50/50) DL-lactide and ε-caprolactone in a 65/35 (mol/mol) ratio usingthe appropriate amount of 1,4-butanediol and PEG1000 as initiators andstannous octoate as catalyst. After reaction at 130° C. for 8 days,¹H-NMR showed complete monomer conversion.

Example 5 Synthesis of Segmented Co-polyesters with Randomly DistributedSegments: P(CL-DLLA): poly(caprolactone-DL-lactide)

Poly-caprolactone pre-polymers with Mn=2000, 3000 or 4000 of Example 3and DL-lactide-ε-caprolactone (50:50) pre-polymer of Example 2 wereweighed in the appropriate amounts into a glass ampoule supplied withnitrogen inlet and a mechanical stirrer. 1 equivalent of1,4-butanediisocyanate (Bayer, distilled at reduced pressure) was added.The contents of the ampoule were quickly heated to 65° C. and thenstirred mechanically for 15 minutes. As the mixture became viscous, thetemperature was increased to 80° C. Stirring was stopped when themixture became too viscous and the heating was continued for a maximumof 24 hours.

De ampoule was cooled to room temperature and the contents were isolatedby dissolving the polymer in chloroform. The solution was filtered andpoured into a petri-dish. The solvent was evaporated and after that thepolymer film was dried in a vacuum oven at 40° C. In another method, thepolymer solution was precipitated in ethanol or other suitable organicsolvent, after which the polymer was isolated and dried.

Polymer composition is determined by ¹H-NMR. The intrinsic viscosityvaried from 1-4 dl/g. The glass transition temperatures of thecopolymers varied from −14° C. to −27° C.; the melting temperatures ofthe crystalline phase was between 39° C. and 60° C., Generally, thehigher the ε-caprolactone content and ε-caprolactone pre-polymer length,the higher the melting temperature and energy. In Table 1 the thermalproperties of a few segmented polyesters are shown. The intrinsicviscosities of these specific copolymers were between 1.2 and 2 dl/g.

Example 6 Synthesis of 10 wt. % PEG Containing Polyurethane withBDI-BDO-BDI-BDO-BDI Hard Segment and PEG1000 and BDO Initiated (65/35)(DL-lactide-ε-caprolactone) Pre-Polymer Soft Segment

A pre-polymer was prepared according to the method of Example 4. Areaction product of two molecules of butanediol (BDO) with1,4-butanediisocyanate (BDI) was used as chain-extender (BDO-BDI-BDO).The preparation was carried out according to the method given ininternational application PCT/NL99/00352. The chain-extender wassubsequently purified, such that a purity of at least 97% was obtained.The melting point of the chain-extender was 98° C.

In the first step of the polyurethane synthesis, the hydroxyl terminatedpre-polymer was end-capped with a 5 to 6 fold excess of1,4-butanediisocyanate under mechanical stirring. After reaction at 60°C. for 4 hours the excess BDI was removed by distillation under reducedpressure.

In the next step of the polymerization, the macrodiisocyanate was chainextended at 65° C. with the BDO-BDI-BDO chain extender using 1,4-dioxaneas solvent (40% w/w). The chain-extender was added in small portions tothe well stirred pre-polymer solution. When the solution became moreviscous, the mixture was diluted with small amounts of dioxane. When theviscosity did not increase anymore, the solution was diluted withdioxane to the desired concentration. The polymer solution was frozenafter which it was freeze dried. The solution can also be precipitatedin water or organic solvents or it can be concentrated by evaporationand dried in vacuum. The polyurethane had an intrinsic viscosity of 1, 1dl/g. The obtained polyurethane can be processed into a drain accordingto the methods of Example 7 and 10.

Example 7 Preparation of Drains according to FIGS. 1, 2 by a Dip-CoatingTechnique

General Method:

Drains were prepared of a polymer solution in chloroform or anotherorganic solvent by dip-coating a straight tubular shaped mandrel or amandrel with a funnel shape at one end with this solution, giving drainswith the dimensions and shape of those of FIGS. 1 and 2, respectively.After dipping, the mandrel was placed horizontally and the solvent wasallowed to evaporate during 5 minutes while rotating. This procedure wasrepeated until the desired wall thickness was obtained. The mandrel withthe copolymer layer was placed first in ethanol and after that indistilled water. The tubes were removed from the mandrel and were cutinto the appropriate size. They were placed in ethanol, followed byvacuum drying at 40° C. in order to remove any monomer- and lowmolecular weight residues and organic solvents.

Example 8 Preparation of a Drain of 65:35 (85/15)L/DLactide-ε-caprolactone Copolymer

Drains of a copolymer of Example 1 were prepared according to thegeneral method of Example 7. Mechanical properties of a 30 mm straighttube (without the funnel) part were measured: the initial modulus was2.9 MPa, the stress at 400% strain was 3.3 MPa, the stress at break was20 MPa and the strain at break was 750%.

Example 9 Preparation of Drains from Segmented Polyesters

Drains of multi-block segmented copolymers of Example 5 (polyestersbuild of poly-caprolactone and poly-(50/50)lactide-ε-caprolactoneprepolymers with various ε-caprolactone/lactide ratios and withdifferent pre-polymer lengths) were prepared according to the generalmethod of Example 7. The thermal- and mechanical properties of tubeswith different composition are measured. The results are presented inTables 1 and 2, respectively:

TABLE 1 Thermal properties of different phase separatedpoly(DL-lactide-ε-caprolactone prepolymers. % PCL prepolymer Tg (° C.)Tm (° C.) ΔH (J/g) 33 (Mn = 3000) −16.8 49.0 26.7 40 (Mn = 3000) −17.157.7 32.1 50 (Mn = 2000) −23.1 53.3 27.1

TABLE 2 Mechanical properties of different phase separatedpoly(DL-lactide-ε-caprolactone prepolymers. Elongation at Stress at %PCL prepolymer Modulus (MPa) break (%) break (MPa) 33 (Mn = 3000) 19.51220 15.1 40 (Mn = 3000) 42.1 1330 13.4 50 (Mn = 2000) 31.1 860 8.3

Example 10 Preparation of Drains of Polyurethanes by Dip-Coating

Drains of a polyurethane prepared according to the method of Example 6and with a (50/50) poly(DL-lactide-ε-caprolactone) pre-polymer withoutPEG were prepared according to the general method of Example 7.Mechanical properties of a 30 mm straight tube (without the funnel) partwere measured: the initial modulus was 35 MPa, the stress at 400% strainwas 16 MPa, the stress at break was 41 MPa and the strain at break was1000%.

Example 11 Preparation of Polyurethane Drains by a Spray-CoatingTechnique

Drains of a polyurethane of Example 6 were prepared by a spray-coatingtechnique. A 4% solution of polyurethane in chloroform was sprayed on ahorizontally rotating glass mandrel with a diameter of 36 mm. Thepolymer layer was dried where after the next layers are sprayed untilthe desired thickness is obtained. A drain with a diameter of 36 mm anda wall thickness between 70 and 150 μm was obtained. Drains are removedfrom the mandrel by a similar method as the dip-coated drains.

Example 12 Preparation of a Drain of 68:32 (85/15)L/DLactide-ε-caprolactone Copolymer and DL-lactide-ε-caprolactone BasedPolyurethane

Drains of a blend of a 68:32 (85/15) L/D-Lactide-caprolactone copolymerand a (50/50) poly(DL-lactide-ε-caprolactone) based polyurethane madeaccording to the method of example 6 were prepared according to thegeneral method of Example 7. A 50:50 (w/w) mixture of the polymers wasdissolved in chloroform. Mechanical properties of a 30 mm straight tube(without the funnel) part were measured: the initial modulus was 10 MPa,the stress at 400% strain was 6.7 MPa, the stress at break was 26 MPaand the strain at break was 990%.

1. Drain suitable for draining a human or animal antrum, organ or tissue, characterized in that it comprises an elastic biocompatible, biodegradable synthetic thermoplastic non-chemically-crosslinked polymer, which polymer has at least one softening point of at most mammalian body temperature and an elastic modulus of up to 120 MPa, wherein the biodegradable polymer comprises at least one of a polyester, polycarbonate, polyester-carbonate, polyanhydride, polyurethane or polyamide which are optionally combined with polyether groups, wherein the polyester is a random DL-Lactide-ε-caprolactone copolyester, having a lactide content of 20-75 mol % and the optional polyether is polyethyleneglycol, polypropyleneglycol, copolymers of polyethyleneglycol and polypropyleneglycol or polytetramethyleneoxide (PTMO).
 2. Drain according to claim 1, consisting essentially of said synthetic biodegradable polymer.
 3. Drain according to claim 1, wherein the polymer has at least one softening point (glass transition temperature) of at most 37-° C.
 4. Drain according to claim 1, wherein the fraction of the L-enantiomer or the D-enantiomer of the lactide is from 65-95 mol.
 5. Drain according to claim 1, wherein the polyester, polyester-carbonate and/or polyanhydride is a segmented or block copolymer with randomly or alternating segments or blocks and consisting of at least two blocks with different composition.
 6. Drain according to claim 5, wherein the segments or blocks are phase separated hard and soft segments, characterized by at least two phase transitions, one of them being a glass transition temperature lower than 37-° C., the other a glass transition temperature or melting temperature higher than 37-° C.
 7. Drain according to claim 5, wherein the segments or blocks forming the low temperature transition phase are composed of pre-polymers of or mixtures of cyclic or non-cyclic monomers lactide, glycolide, ε-caprolactone, δ-valerolactone, trimethylenecarbonate, tetramethylenecarbonate, 1,5-dioxepane-2-one, para-dioxanone and/or hydroxyalkanoicacid.
 8. Drain according to claim 5, wherein the copolymer or pre-polymers are obtained by a ring opening polymerization initiated by a diol or di-acid compound.
 9. Drain according to claim 5, wherein the pre-polymers forming the segments are linked by a difunctional aliphatic compound, preferably a diisocyanate, more preferably 1,4-butanediisocyanate.
 10. Drain according to claim 6, wherein the hard segment or block is selected from the group consisting of poly-caprolactone, poly-valerolactone, poly-lactide, poly(lactide-glycolide), poly-para-dioxanone, poly (hydroxybutyricacid), polysebacic acid, poly(dodecanedioicanhydride) pre-polymers, and combinations thereof.
 11. Drain according to claim 1, wherein said polymer is loaded with radiopaque fillers or pharmaceutical components comprising antibiotics, anti-inflammatory agents, peptides and proteins.
 12. Drain according to claim 1, which is provided with perforations.
 13. Nasal drain comprising an elastic biocompatible, biodegradable synthetic thermoplastic non-crosslinked polymer, wherein the polymer has at least one softening point of at most mammalian body temperature and an elastic modulus of up to 120 MPa, wherein the biodegradable polymer comprises at least one of a polyester, polycarbonate, polyester-carbonate, polyanhydride, polyurethane or polyamide which are optionally combined with polyether groups, wherein the polyester is a random DL-Lactide-ε-caprolactone copolyester, having a lactide content of 20-75 mol %, and the optional polyether is polyethyleneglycol, polypropyleneglycol, copolymers of polyethyleneglycol and polypropyleneglycol or polytetramethyleneoxide (PTMO).
 14. Drain, being a nasal drain, according to claim 1, having a wall thickness of 0.05-5.0 mm.
 15. Drain according to claim 1, having a total length of 3-300 mM.
 16. Drain according to claim 1, having an outer diameter of 0.5-50 mm.
 17. Drain according to claim 1, comprising a funnel shaped element on at least one end.
 18. Drain according to claim 17, having a funnel length of 2-20 mm and a funnel diameter of 3-30 mm.
 19. Drain according to claim 1, which is obtainable by dip-coating or spray coating of a polymer solution on a mandrel or extrusion of a polymer.
 20. Method for treating a disorder associated with dysfunction of natural drainage of body fluids from an antrum, organ or tissue comprising introducing a drain according to claim 1 in said antrum, organ or tissue, such that said antrum, organ or tissue is connected with the environment or another location within the body, after which said drain degrades over time and degradation products of said drain are cleared through the digestive channel or said antrum, organ or tissue or absorbed and subsequently metabolized or secreted by the body.
 21. Method according to claim 20, wherein said disorder is selected from (chronic) sinusitis, inflammation of the middle ear, liver disorders, disorders of the gastro-intestinal tract, tear duct disorder, surgical wound drainage, and thoracic disorder.
 22. Method according to claim 20, wherein said drain is introduced in said antrum using at least one of a form of attachment selected from the group consisting of sealant, suture, and staple.
 23. The method of claim 20, comprising performing coloanal anastomosis performing coloanal anastomosis. 